The invention relates to a traffic guidance system for controlling, guiding and/or optimizing traffic movements, wherein a sensor is provided for detecting the momentary traffic situation.
Traffic guidance systems of the kind under discussion are known from practice. For example, a light signal system, whose signal sequence is controlled by automobiles traveling over a magnetic induction loop, already represents a small-scale traffic guidance system, wherein the magnetic induction loop serves as a sensor.
Furthermore, variable speed limit signs are known from practice, wherein the sensor arrangement may be formed by acoustical or optical ultrasonic motion signalers, or infrared motion signalers, or even by light barriers.
In dense traffic networks, there exists the general problem that in most cases the traffic flow in a certain location is dependent on the traffic flow in other locations. If the traffic flow is to be improved as a whole, it will therefore be necessary to influence the traffic likewise in these other locations. In this instance, traffic guidance systems or traffic signs will have to be coordinated as a whole and be interdependent in a certain way.
Normally, these interdependencies are to be determined by expensive, mathematical examinations and simulations, and must then be applied to the coordination of the traffic signs. To this end different steps are necessary. The traffic volume or the traffic situation and the traffic conditions must be detected via sensors in certain locations. These results are then used as a decision basis in a logic process, which supplies instructions for controlling the traffic signs.
The foregoing control of a light signal system at an individual traffic node or intersection, or at a road junction represents the simplest case of application. At such a traffic intersection, all light signal systems are controlled in dependence on one another. In the costliest application, groups of many traffic signs are switched interdependently. In this process, a plurality of nodes or intersections is involved. For such a networking, it is common to use traffic guidance computers, which are provided in a central traffic routing point. For larger or denser traffic spaces, the mathematical treatment or process control of the traffic control is so expensive that only large computers are still in a position of processing the resultant enormous quantities of traffic data and to perform the control within the scope of mathematical traffic models that have so far been very expensive.
The central traffic control in traffic routing points necessitates numerous and extensive telecommunications links between the traffic signs and a traffic routing point. As is known from the traffic theory, an independent control of individual traffic signs at connected traffic intersections or sections of a traffic route may however barely improve the traffic situation. In the past, is has been possible to significantly improve the interrelated traffic situation of major traffic spacesxe2x80x94for example, in citiesxe2x80x94only with the aid of the described, expensive control with central traffic routing points.
For an effective traffic control, it continues to be necessary that nearly every vehicle in the traffic be considered in the control. Problematic is the use of sensors as have been employed so far in the form of induction loops that are to be crossed, motion signalers, or light barriers, in that their recording capacity is restricted to a narrowly predetermined spatial area, namely, for example, the arrangement area of the induction loop that is to be crossed, or the detectable solid angle of the motion signalers or the range covered by the light barrier. On the other hand, the known sensors are problematic, in that they permit a reliable detection of automobiles only in moving traffic. However, if heavy traffic has already caused a jam, in which the automobiles are stopped, both induction loops and motion signalers, as well as a light barrier will not be able to detect a further increase in the number of automobiles in the observed traffic space or in the jam. The same situation will result, when vehicles are stopped at a light signal system.
From this follows that in particular at times of an already jamming traffic, it is not possible to receive exact data concerning the number of vehicles involved. Consequently, in most cases, the inaccurate or incomplete data will not permit a precise traffic control. Instead, the limits of conventional traffic guidance systems are reached with a therefrom-resulting collapse of the traffic.
It is therefore the object of the present invention to describe a traffic guidance system of the initially described kind, which enables an effective control of traffic movements even in the case of a heavy traffic volume.
The above and other objects and advantages of the invention are achieved by the provision of a traffic guidance system for controlling, guiding, and/or optimizing traffic movements along a roadway, comprising a transmitter carried by each of a plurality of roadway users for actively transmitting a signal irrespective of the state of movement of the user. Also, a sensor is mounted at a fixed location along the roadway for receiving the signals from the transmitters and processing the signals in a decentralized manner at the location where they are received to determine the number of participating roadway users and enable an effective control of traffic movements. Preferably, the traffic guidance system of the invention is configured such that the sensor comprises a radio receiver, and/or a receiver for optical signals, and/or a receiver for acoustical signals emitted by the roadway users.
To begin with, it has been recognized in accordance with the invention that a traffic guidance system is not limited to conventional types of detection. In a further manner according to the invention, the sensor is designed and constructed such that it comprises a radio receiver, and/or a receiver for optical signals, and/or a receiver for acoustical signals, for radio signals, and/or optical signals, and/or acoustical signals, which are actively emitted by road users. With that, limits of conventional types of detection are overcome, since detection of automobiles or other road users is not dependent on their state of movement. Instead, the detection principle of the present invention makes it possible to reliably detect all vehicles, even when same are stopped at a light signal system or in a jam. Furthermore, the spatially narrow detection range, as exists, for example, in the case of a light barrier system, is considerably extended. In a simple manner, it is possible to predetermine the detected spatial area respectively by the configuration of the receiver or the spatial reception coverage.
Consequently, the traffic guidance system of the present invention makes it possible to detect substantially more exact data concerning the number of participating road users. From this results a considerably more representative data base for a traffic guidance system than has been possible with conventional traffic guidance systems. In particular, an accurate data acquisition is possible even in a stopped traffic.
Therefore, the traffic guidance system of the present invention describes a system, which enables an effective control of traffic movements, even in a heavy traffic volume.
As regards a particular simple configuration of the traffic guidance system, it would be possible to associate the sensor to a traffic sign, preferably a light signal system. In a cost-favorable manner, this would make separate sensor carriers unnecessary, such as, for example, carrier poles.
To ensure a reliable detection of the road users, it would be possible to associate to the road users radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters for emitting the radio signals and/or optical signals and/or acoustical signals. In this instance, it would be possible to associate the transmitters to the vehicles of the road users and/or to arrange same thereon. This would realize a link between transmitter and vehicle, so that the transmitter will always be ready for use, when the respective vehicle is used. With that, the road user would not have to see to it that the transmitter is taken along each time the vehicle is used.
As regards a particularly inconspicuous and compact installation of the radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters, it would be possible to integrate the transmitters as subassemblies or as modules in telecommunications equipment, telemetric devices, radio receivers, or other electric equipment. In this connection, an integration in mobile telephones is possible. For example, known mobile telephones transmit radio signals at regular intervals for their own localization by the network operator. Within the scope of the traffic guidance system according to the invention, it would be possible to use these radio signals for detecting the road user. As a whole, it would be possible to provide the radio signals, and/or optical signals, and/or acoustical signals as periodic transmitting pulses with predeterminable transmitting frequencies.
As regards a particularly comfortable operation of the traffic guidance system, it would be possible to associate to the sensors radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters, processing units with memories, and switching devices. This would permit receiving and processing traffic data or the momentary traffic situation for controlling the traffic signs, for example, a plurality of light signal systems of a traffic node, directly in situ, at the respective traffic node. In this instance, the traffic data for controlling the traffic could be collected and processed totally decentralized through the sensors, preferably the radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals.
In particular with respect to a very reliable operation of the traffic guidance system, it would be possible to design and construct the radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals for purposes of detecting and preferably storing signal pulse rates and their changes and/or the received power and its change. Preferably, it would be possible to register regularly transmitted transmitting pulses of the road users moving past a traffic sign, or stopping at a traffic sign, or approaching a traffic sign from a distance. Processing could occur by an internal comparison at each traffic sign, or by a comparison between interdependent traffic signs in a traffic node. To this end, it would be possible to configure the transmitters and receivers of traffic signs, which are to be switched interdependently, in particular traffic signs of a traffic node or a section of a traffic route, in particular for a wireless communication with one another. Processing could occur at certain time intervals or continuously.
In the traffic control, it would also be possible to consider in a particularly effective manner, the respective speeds of the road users and/or their group speed. This could occur, for example, by a radio transmission, an optical or an acoustical transmission of the momentary speed value of the road user to the radio receiver, and/or receiver for optical signals, and/or receiver for acoustical signals of the sensor. On the other hand, it would be possible to design and construct the radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals for detecting and preferably storing the Doppler shift of the signal frequencies of the moving road users and, thus, the state of movement of the road users. This would enable the sensor to determine the speed of the road users automatically. In this instance, the road users would not have to be equipped for transmitting their speed value by means of the radio link, optical connection, or acoustical connection.
To realize a particularly versatile and comprehensive traffic guidance system of a major traffic space, it would be possible that predeterminable groups of interdependent traffic signs, preferably groups, which can be associated to different traffic nodes or sections of traffic routes, are networked by the traffic flow on the traffic routes, and/or are mutually influenceable. With that, it would be possible to transmit by means of the road users themselves data from one group of traffic signs to another group or other groups of traffic signs. Further signal transmitting devices would then not be needed, and the entire radio communications volume and/or optical and/or acoustical signal volume could be limited to spatially narrow areas, for example, an area closely defined around the observed group.
In particular to this end, it would be possible to associate to the radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters, radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals, processing units with memories, and switching devices. Lastly, it would be possible to design and construct the radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters, and radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals, which are associated to the road users and/or traffic signs, as a radio relay, and/or optical signal relay, and/or acoustical signal relay. This would enable a data transmission, and/or a transmission of switching signals in any desired manner via traffic signs and road users.
As regards a particularly sensitive traffic control, the signals of different groups of road users could differ, preferably necessitated by a situation. In this connection, it would be possible to classify, for example, public means of transportation as preferred road users based on their specific radio signals, and/or optical signals, and/or acoustical signals, and to guide same accordingly with preference. Should the respective vehicles in use as means of public transportation be no longer in use, it would be possible to modify the signals accordingly, so that it is no longer necessary to give these vehicles a priority position in the traffic control.
As an alternative or in addition thereto, it would be possible to influence the predeterminable switching behavior of the traffic signs via radio signals, and/or optical signals, and/or acoustical signals. In particular in this connection, one has in mind a priority signal by, for example, squad cars of the police, fire trucks, or ambulances. This would allow to realize a safe passage of such privileged vehicles through intersections, since it would be possible to stop crossing traffic automatically by means of correspondingly controlled traffic signs.
A further, comfortable and effective configuration of the traffic guidance system would permit switching traffic signs based on a comparison of received traffic data and/or received weather data. In this instance, the control of the traffic could be made dependent on individual weather situations. To this end, the radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals could be designed and constructed in a particularly reliable and practical manner for detecting and preferably storing the field attenuation of the radio signals, and/or optical signals, and/or acoustical signals of preferably the road users and, thus, the weather situation, in particular the snow, rain, or fog situation. Depending on the characteristic damping of the signals, it is possible to determine, for example, the density of snow, rain, and fog. On the one hand, the signals could be emitted by the road users, who are in the traffic with vehicles, and on the other hand by road users, who are on their way with bicycles or even on foot. For picking up the weather situation, the signals need not absolutely originate from automobile drivers, but could also come from other road users, whose signals could differ from the signals of the automobile drivers. Thus, the pickup and evaluation of the weather situation is independent of the traffic volume formed by automobiles.
In an effective manner, it would be possible to influence the switching behavior of the traffic signs by an optimization process. In this connection, the optimization process could be a method of varying the parameters that influence the switching process. Parameters could include the traffic volume with a facultative consideration of the weather situation.
As regards a particularly fast control process, the switching of one traffic sign, which is dependent on another traffic sign, could be effected by the other traffic sign. This would make it possible to transmit in particular fast priority signals without undergoing a processing procedure.
As a whole, the traffic guidance system could be constructed as a neural traffic guidance network system. In this instance, the usual operating principles of a neural network are applied.
A further, particularly advantageous development would permit constructing the traffic guidance system in addition as a navigation system for road users. To this end, it would be possible to design and construct the radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters, and radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals of traffic signs for communicating with radio transmitters, and/or optical signal transmitters, and/or acoustical signal transmitters, and radio receivers, and/or receivers for optical signals, and/or receivers for acoustical signals of road users, and vice versa. On the other hand, a pure navigation system without traffic control would likewise be possible by picking up traffic data. In this instance, it would be possible to realize the functions described in the following.
Programmable information via geographic and/or topological characteristics of the traffic routes, in particular an information about traffic destinations of the road users could be stored decentralized in a memory. In this connection, it would be of special advantage that not every road user would have to carry along geographic and/or topological data, which are normally stored on a compact disk.
In a particularly simple manner, it would be possible to associate the memory for the information to a traffic sign. This would allow a constant recall by a requesting road user within the scope of an only short signal connection path.
The information about traffic destinations could be stored in groups, which are associated to the directions of traffic destinations. In this instance, the road user would be referred to the direction of his desired destination. In this process, further possible destinations located in this direction would be passed on to the road user for advertising purposes. In this connection, one has in mind business enterprises, such as, for example, retail businesses, which can be included in the information memory against a certain payment. Likewise, it would be possible to make a request by the road user chargeable, so that the one or both last-mentioned measures would realize a financing of the operation and actualization of the memory. Thus, a further traffic guidance function would be realized by means of the navigation system.
The results, which are present in the case of detecting the weather situation by the sensors, could likewise be made available to a road user upon request. Thus, the traffic guidance system could be constructed in addition as a weather information system. Likewise, this request could be made chargeable. In this connection and in the case of the navigation system, the request via a mobile telephone presents itself in particular. In this instance, its network operator could charge the fees.
A regards a comprehensive use of the traffic guidance system, it would be possible to make available an electronic device, which is characterized by a radio receiver, and/or receiver for optical signals, and/or receiver for acoustical signals for the radio signals, and/or optical signals, and/or acoustical signals, which are emitted by the road users. In a simple manner, such devices could be used as supplemental components for traffic signs already in use.
Furthermore, it would also be possible to make available electronic devices, which are characterized on the part of the road user by a radio transmitter, and/or optical signal transmitter, and/or acoustical signal transmitter for emitting radio signals, and/or optical signals, and/or acoustical signals for the traffic guidance system. With that, it would also be possible to realize an ideal possibility of retrofitting automobiles.